What is a kidney stone?
When crystals form and separate from urine in a urinary tract, they can create kidney stones. Urine normally creates chemicals that inhibit stone formation, but these inhibitors don’t always work. Many crystals remain tiny and pass unnoticed. Some are composed in a way that give them more mass.
The most common type of stone is composed of calcium (an important building block of your bones and muscles) combined with oxalate and phosphate. These chemicals are part of a normal diet.
Infection in the urinary tract can also cause stones. Though less common, it’s still possible. Your doctor will call this a struvite, or infection stone. Uric acid stones and cystine stones are rarest of all. When a stone occurs in the urinary tract, this is known as urolithiasis, urinary tract stone disease, or nephrolithiasis.
To draw a greater distinction, a stone in the ureter is called ureterolithiasis. For our purposes, we’re calling everything kidney stones. Please note that kidney stones and gallstones are not related. They form in different areas of the body, and someone with one is not necessarily more likely to develop the other.
Below the ribs and toward the middle of your back lie two bean-shaped organs, one on each side of the spine. These are your kidneys, and they remove extra water and waste from your blood, producing urine. They also balance salts and other substances in your blood. Kidneys also produce hormones that help strengthen bones and form red blood cells.
Urine is carried from the kidneys to the bladder through narrow tubes called ureters. From there, urine goes to the bladder. The bladder expands like a balloon to store urine. When you empty your bladder, the urine travels through the ureter and the bladder and ureters flatten.
Who gets kidney stones?
For unknown reasons, the occurrence of kidney stones has been on the rise. In the late 1970s, less than four percent of people in the United States had stone-forming disease. By the early 1990s, that percentage increased to more than five.
Caucasians are more prone to develop kidney stones than African Americans. Stones occur more frequently in men. The prevalence of kidney stones rises dramatically as men enter their 40s and continues to rise into their 70s.
For women, the prevalence of kidney stones peaks in their 50s. Once a person gets more than one stone, other stones are likely to develop.